Conventional image-displaying electronic devices include devices that display an image on a predetermined display screen, such as cathode-ray tubes and liquid crystal displays, and devices that project an image on a wall surface or a screen, such as projectors.
The most common projectors are known as “stationary projectors”, which receive power from a commercial power supply and operate in a certain fixed position. Stationary projectors project, in a fixed position, an image on a fixed position of a wall surface or a screen. Portable projectors have been proposed recently that are small and easy to carry around. For example, Patent Literature 1 describes a projector-function-equipped mobile terminal that includes an upper cabinet, a lower cabinet, and a hinge unit that rotatably joins the upper cabinet and the lower cabinet together, and the terminal also includes a projector that includes a lens and a light source.
Some electronic devices have both an image displaying function and an image taking function. For example, Patent Literature 2 describes a projector device that includes a projector unit that projects a projection image received from an external device on a screen; an image taking unit that takes an image of the screen and creates the taken image; and a written-data storage unit that stores therein written data that is directly written onto the screen in association with the projector image.